1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Generic watchdog defines. Derived from.. 4 * 5 * Berkshire PC Watchdog Defines 6 * by Ken Hollis <khollis@bitgate.com> 7 * 8 */ 9 #ifndef _LINUX_WATCHDOG_H 10 #define _LINUX_WATCHDOG_H 11 12 13 #include <linux/bitops.h> 14 #include <linux/cdev.h> 15 #include <linux/device.h> 16 #include <linux/kernel.h> 17 #include <linux/notifier.h> 18 #include <uapi/linux/watchdog.h> 19 20 struct watchdog_ops; 21 struct watchdog_device; 22 struct watchdog_core_data; 23 struct watchdog_governor; 24 25 /** struct watchdog_ops - The watchdog-devices operations 26 * 27 * @owner: The module owner. 28 * @start: The routine for starting the watchdog device. 29 * @stop: The routine for stopping the watchdog device. 30 * @ping: The routine that sends a keepalive ping to the watchdog device. 31 * @status: The routine that shows the status of the watchdog device. 32 * @set_timeout:The routine for setting the watchdog devices timeout value (in seconds). 33 * @set_pretimeout:The routine for setting the watchdog devices pretimeout. 34 * @get_timeleft:The routine that gets the time left before a reset (in seconds). 35 * @restart: The routine for restarting the machine. 36 * @ioctl: The routines that handles extra ioctl calls. 37 * 38 * The watchdog_ops structure contains a list of low-level operations 39 * that control a watchdog device. It also contains the module that owns 40 * these operations. The start and stop function are mandatory, all other 41 * functions are optional. 42 */ 43 struct watchdog_ops { 44 struct module *owner; 45 /* mandatory operations */ 46 int (*start)(struct watchdog_device *); 47 int (*stop)(struct watchdog_device *); 48 /* optional operations */ 49 int (*ping)(struct watchdog_device *); 50 unsigned int (*status)(struct watchdog_device *); 51 int (*set_timeout)(struct watchdog_device *, unsigned int); 52 int (*set_pretimeout)(struct watchdog_device *, unsigned int); 53 unsigned int (*get_timeleft)(struct watchdog_device *); 54 int (*restart)(struct watchdog_device *, unsigned long, void *); 55 long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long); 56 }; 57 58 /** struct watchdog_device - The structure that defines a watchdog device 59 * 60 * @id: The watchdog's ID. (Allocated by watchdog_register_device) 61 * @parent: The parent bus device 62 * @groups: List of sysfs attribute groups to create when creating the 63 * watchdog device. 64 * @info: Pointer to a watchdog_info structure. 65 * @ops: Pointer to the list of watchdog operations. 66 * @gov: Pointer to watchdog pretimeout governor. 67 * @bootstatus: Status of the watchdog device at boot. 68 * @timeout: The watchdog devices timeout value (in seconds). 69 * @pretimeout: The watchdog devices pre_timeout value. 70 * @min_timeout:The watchdog devices minimum timeout value (in seconds). 71 * @max_timeout:The watchdog devices maximum timeout value (in seconds) 72 * as configurable from user space. Only relevant if 73 * max_hw_heartbeat_ms is not provided. 74 * @min_hw_heartbeat_ms: 75 * Hardware limit for minimum time between heartbeats, 76 * in milli-seconds. 77 * @max_hw_heartbeat_ms: 78 * Hardware limit for maximum timeout, in milli-seconds. 79 * Replaces max_timeout if specified. 80 * @reboot_nb: The notifier block to stop watchdog on reboot. 81 * @restart_nb: The notifier block to register a restart function. 82 * @driver_data:Pointer to the drivers private data. 83 * @wd_data: Pointer to watchdog core internal data. 84 * @status: Field that contains the devices internal status bits. 85 * @deferred: Entry in wtd_deferred_reg_list which is used to 86 * register early initialized watchdogs. 87 * 88 * The watchdog_device structure contains all information about a 89 * watchdog timer device. 90 * 91 * The driver-data field may not be accessed directly. It must be accessed 92 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers. 93 */ 94 struct watchdog_device { 95 int id; 96 struct device *parent; 97 const struct attribute_group **groups; 98 const struct watchdog_info *info; 99 const struct watchdog_ops *ops; 100 const struct watchdog_governor *gov; 101 unsigned int bootstatus; 102 unsigned int timeout; 103 unsigned int pretimeout; 104 unsigned int min_timeout; 105 unsigned int max_timeout; 106 unsigned int min_hw_heartbeat_ms; 107 unsigned int max_hw_heartbeat_ms; 108 struct notifier_block reboot_nb; 109 struct notifier_block restart_nb; 110 void *driver_data; 111 struct watchdog_core_data *wd_data; 112 unsigned long status; 113 /* Bit numbers for status flags */ 114 #define WDOG_ACTIVE 0 /* Is the watchdog running/active */ 115 #define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */ 116 #define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */ 117 #define WDOG_HW_RUNNING 3 /* True if HW watchdog running */ 118 #define WDOG_STOP_ON_UNREGISTER 4 /* Should be stopped on unregister */ 119 struct list_head deferred; 120 }; 121 122 #define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT) 123 #define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT) 124 125 /* Use the following function to check whether or not the watchdog is active */ 126 static inline bool watchdog_active(struct watchdog_device *wdd) 127 { 128 return test_bit(WDOG_ACTIVE, &wdd->status); 129 } 130 131 /* 132 * Use the following function to check whether or not the hardware watchdog 133 * is running 134 */ 135 static inline bool watchdog_hw_running(struct watchdog_device *wdd) 136 { 137 return test_bit(WDOG_HW_RUNNING, &wdd->status); 138 } 139 140 /* Use the following function to set the nowayout feature */ 141 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout) 142 { 143 if (nowayout) 144 set_bit(WDOG_NO_WAY_OUT, &wdd->status); 145 } 146 147 /* Use the following function to stop the watchdog on reboot */ 148 static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd) 149 { 150 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status); 151 } 152 153 /* Use the following function to stop the watchdog when unregistering it */ 154 static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd) 155 { 156 set_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status); 157 } 158 159 /* Use the following function to check if a timeout value is invalid */ 160 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t) 161 { 162 /* 163 * The timeout is invalid if 164 * - the requested value is larger than UINT_MAX / 1000 165 * (since internal calculations are done in milli-seconds), 166 * or 167 * - the requested value is smaller than the configured minimum timeout, 168 * or 169 * - a maximum hardware timeout is not configured, a maximum timeout 170 * is configured, and the requested value is larger than the 171 * configured maximum timeout. 172 */ 173 return t > UINT_MAX / 1000 || t < wdd->min_timeout || 174 (!wdd->max_hw_heartbeat_ms && wdd->max_timeout && 175 t > wdd->max_timeout); 176 } 177 178 /* Use the following function to check if a pretimeout value is invalid */ 179 static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd, 180 unsigned int t) 181 { 182 return t && wdd->timeout && t >= wdd->timeout; 183 } 184 185 /* Use the following functions to manipulate watchdog driver specific data */ 186 static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data) 187 { 188 wdd->driver_data = data; 189 } 190 191 static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) 192 { 193 return wdd->driver_data; 194 } 195 196 /* Use the following functions to report watchdog pretimeout event */ 197 #if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV) 198 void watchdog_notify_pretimeout(struct watchdog_device *wdd); 199 #else 200 static inline void watchdog_notify_pretimeout(struct watchdog_device *wdd) 201 { 202 pr_alert("watchdog%d: pretimeout event\n", wdd->id); 203 } 204 #endif 205 206 /* drivers/watchdog/watchdog_core.c */ 207 void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority); 208 extern int watchdog_init_timeout(struct watchdog_device *wdd, 209 unsigned int timeout_parm, struct device *dev); 210 extern int watchdog_register_device(struct watchdog_device *); 211 extern void watchdog_unregister_device(struct watchdog_device *); 212 213 /* devres register variant */ 214 int devm_watchdog_register_device(struct device *dev, struct watchdog_device *); 215 216 #endif /* ifndef _LINUX_WATCHDOG_H */ 217